This application relates generally to gas turbine engines and, more particularly, to gas turbine engine compressors.
A gas turbine engine typically includes a multi-stage axial compressor with a number of compressor blade or airfoil rows extending radially outwardly from a common annular rotor rim. An outer surface of the rotor rim typically defines a radially inner flowpath surface of the compressor as air is compressed from stage to stage. An interior area within the rotor rim is referred to as a compressor bore and typically includes a secondary flow cooling circuit. Airflow of a sufficient pressure and temperature supplied to the secondary flow cooling circuit is used to drive secondary flow cooling circuit components including sump hardware.
Compressor bleed air is often directed to the secondary flow cooling circuit. However, the temperature of the compressor bleed air limits the locations in which compressor air extraction may occur. Higher temperature bore cooling airflows may reduce strength of the compressor rotor components, while cooler temperature bore cooling airflows typically have insufficient pressure to drive such compressor bore cooling circuits. To increase the compressor bore cooling circuit pressure, bleed air may be extracted further aft in the compressor flowpath. Typical bleed air systems include complicated delivery systems. Delivery system components use complex attachment schemes with additional hardware. The additional hardware adds to the overall compressor rotor weight, and thus, affects the performance of the gas turbine engine. As a result, both assembly time and potential of failure of both the additional hardware and the compressor rotor components are increased.
In an exemplary embodiment, a gas turbine engine includes a compressor rotor assembly which effectively directs air at a sufficient pressure and temperature to a compressor rotor bore. The compressor assembly includes a compressor including a plurality of rotors joined with a plurality of couplings. Each rotor includes a radially outer rim, a radially inner hub, and a web extending between the outer rim and the inner hub. The web includes a flange having a front face, a rear face and a plurality of openings extending from the front face to the rear face and sized to receive the couplings. The flange front face includes a plurality of slots which define a plurality of radial vanes that are airfoil-shaped.
In operation, compressor bleed air exits compressor first stage stator vanes with a free vortex swirl. The radial vanes rotate simultaneously with the compressor rotor assembly and re-direct the compressor bleed air against the free vortex direction towards the compressor bore. The rotation and shape of the airfoil cause the airflow to be deswirled as it passes through the slots. As a result, the pressure loss due to the free vortex swirl is minimized and the compressor bore receives airflow of a sufficient pressure and temperature.